There is widespread use and exposure of pregnant women and their infants to pesticides but limited data is available on the long term effects of these neurotoxicants on the growth and neurodevelopment of the children. We propose to continue the longitudinal study (up to age 6 years) of our cohort (N=754) of infants, a high percentage of whom were antenatally exposed to propoxur, bioallethrin, cyfluthrin and cypermethrin (heretofore referred to as pesticides). We have tested these infants up to 2 years of age using the Fagan Test of Infant Intelligence and Griffiths'Mental Development Scales. At 2 years, neurobehavioral testing revealed a significant decrease in Griffiths performance in association with prenatal exposure of the infants, particularly to propoxur. We intend to study the progress of these deficits and to uncover any delayed neurotoxic effects of pesticide exposure in these children. AIMS: (1) To examine the relationship between antenatal exposure to pesticides and neurobehavioral development of children at 4 and 6 years of age, (2) To examine the relationship between postnatal exposure to pesticides, as measured by analysis of house dust and children's hair, and neurobehavioral development of children at 4 and 6 years, and (3) To examine the relationship between prenatal and postnatal exposure to pesticides and neurobehavioral development at 4 and 6 years. We hypothesize that there will be more neurodevelopmental deficits associated with prenatal or postnatal exposure to pesticides compared to the unexposed group and the deficits will be more pronounced with both pre- and postnatal exposures. METHODS: At 4 and 6 years of age, hair from children in our ongoing study cohort, as well as house dust from their homes, will be collected and analyzed for pesticides by gas chromatography/ mass spectrometry to detect ongoing exposure. The children will be tested at 4 and 6 years with a battery of tests which assess: (1) General cognition, (2) Attention &executive function, (3) Memory, (4) Behavior and (5) Self help. These tests explore the domains and functions of the brain that are affected by pesticides in animal and human studies. DATA ANALYSIS: The outcome measures from these tests will be correlated, after adjustment for confounders, to pre- and/or postnatal exposure to pesticides. PUBLIC HEALTH RELEVANCE: This study utilizes a large cohort of infants for whom we have data on prenatal and early childhood pesticide exposure, as well as assessments of growth and neurodevelopment from birth up to 2 years of age, with a 95% follow up rate. The study is important and relevant to public health since it will provide important and much needed information on the longitudinal, adverse effects on the growth and neurodevelopment of children of carbamates and pyrethroids, which are now widely used. The study is important and relevant to public health since it will provide important and much needed information on the longitudinal, adverse effects on the growth and neurodevelopment of children of carbamates and pyrethroids, which are now widely used.